[room500]

Non-cynically, it probably does introduce some issues in these legacy telecom systems.

For example, if you run out of data for a month, many carriers will continue giving you access to the internet APN, but then block access to "external" websites. This is so you can easily open your browser and "top up" on data to continue using your device.

Or the usage of HTTP (not HTTPS) was relatively common back when I was in the space (7-10 years ago). There wasn't a need to use HTTP because the carrier was in full control of the pipe between the device and the server. Adding in a VPN that somehow tries to intercept that traffic (that was supposed to exist entirely within the telecom) is not going to work.

[josephcsible]

But if that were the only reason why, then couldn't they just turn off Private Relay in that specific case, instead of all the time?